Crane

Abstract

A crane includes: a boom; a jib that is provided on a leading end side of the boom; and a strut that is provided at one or both of a leading end portion of the boom and a base end portion of the jib, and to which a jib support pendant is connected, the strut, to which the pendant is connected, being provided with strut rotationally moving means having: a first bar-like member rotationally connected, at a first end portion thereof on one side, to a leading end portion of the strut on an opposite side thereof to a side, on which the pendant is connected; and a direct acting apparatus that applies, to the first bar-like member, a force pulling the first bar-like member toward the other side along a longitudinal direction of the first bar-like member.

What is claimed is: 
     
       1. A crane comprising:
 a boom; 
 a jib that is provided on a leading end side of the boom; and 
 a strut that is provided at one or both of a leading end portion of the boom and a base end portion of the jib, and to which a jib support pendant is connected, 
 the strut, to which the pendant is connected, being provided with strut rotationally moving means having: a first bar-like member rotationally connected, at a first end portion thereof on one side, to a leading end portion of the strut on an opposite side thereof to a side, on which the pendant is connected; and a direct acting apparatus that applies, to the first bar-like member, a force pulling the first bar-like member toward the other side along a longitudinal direction of the first bar-like member. 
 
     
     
       2. The crane according to  claim 1 , wherein the strut rotationally moving means serves as a toggle mechanism in which an articulated portion is pushed and pulled by a force of the direct acting apparatus, this articulated portion being formed by connecting, in a stretchable manner, a second end portion of the first bar-like member, whose first end portion is connected to the leading end portion of the strut, with a second bar-like member which is different from the first bar-like member. 
     
     
       3. The crane according to  claim 2 , wherein the toggle mechanism pushes and pulls the articulated portion of the first bar-like member and the second bar-like member by means of an articulated-portion-driving toggle-mechanism having two link pieces joined together so as to rotate freely and a direct acting apparatus connected to a joining portion between the link pieces. 
     
     
       4. The crane according to  claim 3 , wherein a first link piece of the two link pieces of the articulated-portion-driving toggle-mechanism which is proximate to the strut provided with the strut rotationally moving means is provided so as to have a rotation center disposed coaxially with a rotation center of the strut, and the first link piece comprises means for removably locking the first link piece on the strut so that the first link piece is rotationally moved integrally with the strut. 
     
     
       5. The crane according to  claim 1 , wherein the first bar-like member, the first end portion of which is connected to the leading end portion of the strut, comprises a contraction mechanism provided in a middle of the longitudinal direction of the first bar-like member and enabling the first bar-like member to contract all over a length thereof.